Calculations of X-ray wave propagation in large objects are needed for modeling diffractive X-ray optics and for optimization-based approaches to image reconstruction for objects that extend beyond the depth of focus. We describe three methods for calculating wave propagation with large arrays on parallel computing systems with distributed memory: (1) a full-array Fresnel multislice approach, (2) a tiling-based short-distance Fresnel multislice approach, and (3) a finite difference approach. We find that the first approach suffers from internode communication delays when the transverse array size becomes large, while the second and third approaches have similar scaling to large array size problems (with the second approach offering about three times the compute speed).

中文翻译：

---

非均匀介质中 X 射线波传播的分布式存储算法比较

需要计算大型物体中的 X 射线波传播，以对衍射 X 射线光学进行建模，以及对超出焦深的物体进行基于优化的图像重建方法。我们描述了在具有分布式内存的并行计算系统上使用大型阵列计算波传播的三种方法：(1) 全阵列菲涅尔多切片方法，(2) 基于平铺的短距离菲涅耳多切片方法，以及 (3) 有限差异方法。我们发现，当横向阵列尺寸变大时，第一种方法会受到节点间通信延迟的影响，而第二种和第三种方法对大阵列尺寸问题具有相似的缩放比例（第二种方法提供大约三倍的计算速度）。